Gorman-Rupp Pumps 16C20-F5L 1338868 and up - Manual (Page 13)

OM−02616 10 SERIES
PAGE B − 6 INSTALLATION
ameter to minimize the chance of plugging.
In low discharge head applications (less than 30
feet (9,1 m)), it is recommended that the bypass
line be run back to the wet well, and located 6
inches below the water level or cut-off point of the
low level pump. In some installations, this bypass
outline may be terminated with a six-to-eight foot
(1,8 to 2,4 m) length of 1-1/4 inch (31,8 mm) I.D.
smooth-bore hose; air and liquid vented during
the priming process will then agitate the hose and
break up any solids, grease, or other substances
likely to cause clogging.
A bypass line that is returned to a wet well
must be secured against being drawn into
the pump suction inlet.
It is also recommended that pipe unions be in-
stalled at each 90
_ elbow in a bypass line to ease
disassembly and maintenance.
In high discharge head applications (more than
30 feet (9,1 m), an excessive amount of liquid may
be bypassed and forced back to the wet well under
the full working pressure of the pump; this will re-
duce overall pumping efficiency. Therefore, it is
recommended that a Gorman-Rupp Automatic
Air Release Valve be installed in the bypass line.
Gorman-Rupp Automatic Air Release Valves are
reliable, and require minimum maintenance. See
Automatic Air Release Valves in this section for
installation and theory of operation of the Auto-
matic Air Release Valve. Consult your Gorman-
Rupp distributor, or contact the Gorman-Rupp
Company for selection of an Automatic Air Release
Valve to fit your application.
Except in certain specific applications (to
prevent flooding during service of an auto-
matic air release valve in a below-ground
lift station), if a manual shut-off valve is in-
stalled anywhere in a bypass line, it must
be a full-opening, ball-type valve to pre-
vent plugging by solids.
A manual shut-off valve should not be
installed in any bypass line. A manual
shut-off valve may inadvertently be left
closed during operation. A pump which
has lost prime may continue to operate
without reaching prime, causing dan-
gerous overheating and possible explo-
sive rupture of the pump casing. Per-
sonnel could be severely injured.
Allow an over-heated pump to com-
pletely cool before servicing. Do not re-
move plates, covers, gauges, or fittings
from an over-heated pump. Liquid with-
in the pump can reach boiling tempera-
tures, and vapor pressure within the
pump can cause parts being disen-
gaged to be ejected with great force. Af-
ter the pump completely cools, drain the
liquid from the pump by removing the
casing drain plug. Use caution when re-
moving the plug to prevent injury to per-
sonnel from hot liquid.
AUTOMATIC AIR RELEASE VALVE
When properly installed, a Gorman-Rupp Auto-
matic Air Release Valve will permit air to escape
through the bypass line and then close automati-
cally when the pump is fully primed and pumping
at full capacity.
Some leakage (1 to 5 gallons [3.8 to 19
liters] per minute) will occur when the
valve is fully closed. Be sure the bypass
line is directed back to the wet well or
tank to prevent hazardous spills.
Consult the manual accompanying the Air Release
Valve for additional information on valve installation
and performance.